The present invention relates generally to an insert holder 1 and more particularly to an insert holder for a cutting insert in a turning tool.
In most prior art insert holders, use is made of mechanical clamping means, such as screws or bodies attachable by screws, which hold the cutting insert in engagement with a seat in the insert holder. For insert holders primarily intended for applications where the available working space is small, e.g. for severing and plunge cutting operations, insert holders have previously been suggested, where the cutting insert is clamped by spring action in a seat facing the workpiece. Such an insert holder is formed with a thicker portion below the seat and a somewhat thinner yieldable portion above the seat. To stabilize the cutting insert in lateral direction, its edges, engaging with the sides of the seat, are formed with V-shaped grooves matching V-shaped elevations along the sides of the seat.
In using prior art insert holders, one must rely on the fact that the resilient engaging pressure remains, i.e. that the portion engaging the upper side of the cutting insert is permanently tensioned out of its non-activated position. In this situation there is a considerable risk of fatigue which results in decreasing clamping force and the cutting insert not being unresiliently kept in its seat. Especially when subjected to shock, the cutting insert is liable to be displaced in its seat. Heavy stress can also result in the cutting insert splitting or cracking along its center plane by cooperation between the V-shaped recess on the lower side of the cutting insert and the reversed V shape of the edge of the seat.